The unusual white leaves or leaf portions are unusual but obviously not impossible. Indeed, there is a botanical name for it. Plants that exhibit these uncommon physical characteristics are called "sports." (You can look it up in Wikipedia.) Sports are often prized because of their unusual qualities and are then propagated by cuttings (cloned) to try to preserve those same qualities. Sometimes it works and sometimes the cloned plant reverts back to the original. Sports are often the way that entirely new plant varieties are introduced, propagated and become regularized.
